Buoyant pump with drive train subassembly

ABSTRACT

THE IMPELLER CHAMBER BACKING WALL, FORMERLY AN INWARD EXTENSION OF THE VOLUTE IS CUT AWAY AND A DETACHABLE METAL PLATE SUBSTITUTED, THUS THE IMPELLER, SHAFT, BEARINGS AND SEAL MAY BE WITHDRAWN TOGETHER WITH THE CHAMBER WALL. THE WALL IS DISHED TO FORM AN OIL SUMP SO AS TO ACCOMMODATE A SPEED REDUCER, A SUMP COVER PLATE PROVIDES LOCATIONS FOR MOUNTING THE POWER UNIT.

Jan. 19, 1971 v F. A. MOORE 3,555,535

BUOYANT PUMP WITH DRIVE TRAIN SUBASSEMBLY Filed Jan. 28, 1969 2Sheets-Sheet 1 IN VENTDR FREDERICK R- NDORE HTTORNEyS Jan. 19, 1971 F,A, MOORE 3,555,555

BUOYANT PUMP WITH DRIVE TEA IN SUBASSEMBLY Filed Jan. 28, 1969 2Sheets-Sheet I I/VVEA/ TOR FRBDEIZ/dr n- NOD/YE HTI'DRIVEyS U.S. Cl.417-337 United States Patent 3,556,685 BUOYANT PUMP WITH DRIVE TRAINSUBASSEMBLY Frederick A. Moore, Edmonton, Alberta, Canada, as-

signor to Northwest Industries Limited, Edmonton, Alberta, Canada FiledJan. 28, 1969, Ser. No. 794,743 Claims priority, application Canada,Nov. 29, 1968,

Int. Cl. F04d 13/02, 13/14 8 Claims ABSTRACT OF THE DISCLOSURE Theimpeller chamber backing wall, formerly an inward extension of thevolute is cut away and a detachable metal plate substituted; thus theimpeller, shaft, bearings and seal may be withdrawn together with thechamber wall. The wall is dished to form an oil sump so as toaccommodate a speed reducer; a sump cover plate provides locations formounting the power unit.

This invention relates to the general field of buoyant centrifugal pumpsand specifically to the problem servicing the drive train; more narrowlyit relates to the problem of making a seal in such pumps which willprevent leakage of water into the speed reduction assembly.

In one commercially successful buoyant pump the housing comprises asquat three component structure of thin lightweight material such asmoulded glass reinforced polyester sheet. The upper and middlecomponents are contoured to form a buoyancy chamber, the middlecomponent being reentrant within the buoyancy chamber to form the upperportion of the pump volute. The lower component of the housing forms thelower portion of the pump volute, as well as the lower wall of theimpeller chamber and the inlet to the impeller eye. Such features arecommon to the present invention although not of direct concern and arefurther described later below.

In the prior art, however, the upper and middle moulded sheet componentscontinued separately inwards to a diameter where they were moulded to astiff cylindrical glass polyester support surrounding a central metalsleeve. This sleeve was thus integrally moulded into the assembly of theupper and middle housing pieces and was pro- 'vided with a bearingsurface for the impeller shaft, and lands for retaining shaft seals. Themiddle moulded sheet piece between the volute chamber and the metalsleeve was substantially flat to form the impeller chamber upper wall;the upper piece was formed as a shallow dish to accommodate a speedreduction train between the impeller and an internal combustion enginedrive shaft.

Unfortunately, such an assembly was awkward to service requiringimpeller removal before the shaft could be extracted upwardly from thehousing. Thus, servicing often required return of the whole pump asfield service of a drive train component could not be carried out by areplacement drive train.

Moreover, leakage occurred, not through the shaft-tosleeve seals, butbetween the metal sleeve and the cylindrical polyester surroundnecessitating relatively frequent service. This may have been due torough handling or extreme fluctuation in temperature, as by immersion ofa warm pump in ice cold water; whatever the cause, water leaked into thespeed reduction train displacing the oil and damaging components so asto destroy the drive.

I have discovered that the disadvantages of the prior art pump housingand drive arrangement are overcome by terminating both upper and middlemoulded housing sheets at a radius greater than that of the impeller andsmaller than the volute. This permits the bearing sleeve Patented Jan.19, 1971 to be welded integral :with a support cone which is thensecured to the top of the upper housing piece. This also permits asecond development-that of making the shaft, impeller, sleeve, speedreduction train, and its dish and cover as a unitary subassembly. Yetanother feature over the prior art permitted by the excision of thecentral portion of the upper and middle housing pieces is that theimpeller shaft can be provided with an upper bearing to steady it. Yetother unobvious steps will become apparent on perusal of the descriptionbelow and the claims.

The invention will be more clearly understood by reference to thedrawings in which:

FIG. 1 shows an informative cross section of the pump, and

FIG. 2 shows an oil supply arrangement for one of the pump gears.

In FIG. 1, 2 is the upper structural component of thin sheet materialwhich, with the contoured middle component 4, forms a buoyancy member 6.Buoyancy member 6 is filled with cellular lightweight expanded foam.Handles 7 are fitted to facilitate carrying the pump, A lower component8 also formed from thin sheet stock is contoured so as to cooperate withmiddle piece 4 to form a volute chamber 10, for the pump impeller 12.This lower component extends inwardly as in the prior art to form alower impeller chamber wall 14 Which is faired downwardly to provide acentral inlet 16 to the eye of the impeller. The outlet from the voluteis not shown in this section. It will be understood that by such termsas volute chamber diameter, I would refer to the roughly circular crosssection of 10, and by volute diameter I can a dimension in the plane ofthe impeller 12.

A moulded base 18 having a series of holes 20 and integral stiffeningchannel ribs 22 is bolted to the squat three component structure byself-tapping screws 23 and allows free access of the fluid to be pumpedto the central inlet 16. This base protects the inlet from blockage bymud or damage by stones when the fluid level falls so that the pump isaground, and two sections are shown to assist understanding. It will beunderstood that the selftapping screws, 23, are in fact held byrectangular steel inserts 24 which are trapped between the flat flangeof item 4 and a local overmoulding 25 of polyester resin reinforced bychopped glass roving.

Contrary to the teachings of the prior art, upper and middle formedsheet pieces 2 and 4 terminate inwardly at 26 which corresponds to adiameter slightly greater than that of the pump impeller in a bondedjoint, 28. Preferably this bonded joint is made from catalysed polyesterresin filled with long glass fibre and thixotropic silica to form acement.

An integral assembly of a speed reduction mechanism, casing, shaft andimpeller indicated generally at 30 is bolted to the upper thinstructural piece 2 by self-tapping screws 31. Again, these screws are,in fact, held by rectangular steel inserts 32 trapped between the glasspolyester casing 2 and a local overmoulding 33.

This integral assembly comprises a hollow inverted generally conicalsheet metal member 34 and sleeve 36. I call sheet metal member 34 a wallmeans because it provides the impeller chamber upper wall as well as thesump lower wall. These items are welded together to provide a completelyleak-proof joint, the assembly being termed a sump for reasons givenlater below. The shape of member 34 is not critical, but I have had goodresults with the contour shown which permits good upper and lowersealing welds and represents a good compromise in limited space. Forreasons of lightness, corrosion resistance, relative cheapness and easeof welding and working, the obvious material choice for the sump 34, 36is aluminum although other materials may be used.

This sump 34, 36 is covered by a cast aluminum plate 38 called an enginemounting plate, a sealing gasket 39 being trapped between them. Setscrews hold the sump and plate together to form an enclosure for a speedreduction drive. Although I have chosen to use a gear reduction, andcertain features of the particular gear reduction are unobvious, it willbe apparent to those skilled in the art that other types of speedreducers, such as a chain and sprocket drive could be accommodated inthe enclosure.

An engine, which has mounting feet 42 is fastened to bosses 44 of theengine mounting plate 38 by bolting, 46, 48. The bosses have holes withsufficient clearance to allow accurate location of engine shaft 50. Theengine is not shown in full; I prefer to use a four cycle air cooledengine Tecumseh (Tecumseh is a trademark) model LAV 35 which has arating of 3.5 horsepower at 3,600 r.p.m. but other suitable sizes andtypes of engine or motor may be used, as desired.

This engine shaft passes through an oilite bushing 52 in the enginemounting plate 38 and drives a pinion gear 54 through a Woodrutf key 56.The pinion 54 incorporates a retaining ring 58 which enables it to befastened to engine shaft 50 by means of a ca screw 60 and accompanyingwashers and lock washers. Seepage of water down the shaft is preventedby O-ring 62 which is trapped between the upper surface of double sidedboss 64 for the engine drive bush and the engine shaft spigot land 66.

Pinion gear 54 drives internal annular gear wheel 68 which generallyresembles a shallow cup. This gear wheel 68 is of aluminum cast in apermanent mould about steel hub 67, which is machined to be a press fiton impeller shaft 70, extraction holes 69 being provided to facilitateremoval. Impeller shaft 70 is held between plain journal bearing 72 insleeve 36 and an oilite bush 74 in bOSs 76 on engine mounting plate 38.It will be readily understood that the holes for bush 52 and 74 may bejig drilled together so as to ensure accurate mating for the teeth ofpinion 54, and internal gear 68. It will also be understood that thesection of FIG. 1 has been chosen to give as much information aspossible and is not across a diameter as indicated by the brokensections.

A feature of internal annular gear 68 is that oil for t e teeth surfacesis provided by a tube 78 projecting into the oil sump as shown in FIG.2. Tube 78 is chamfered at both ends at an angle of 45 to the axis, theplanes of each chamfer being at 45 to each other; this tube is set intoa hole drilled at 45 to the bottom inside surface of the internal gear58. The axis of the hole is such that it is substantially tangential tothe circle of rotation of the open end of the tube; thus, as the gearrotates the ch mfered end is vertically disposed and scoops up oil. Theother end, lying flat on the bottom inside surface of the gear 68 allowsthe oil to flow over the bottom surface and up the gear teeth bycentrifugal force. Arrows entering and leaving tube 78 in FIG. 2illustrate the oil flow. I find diameter aluminum tubing set at a radiusof 1%," from the centreline when the reduction ratio is 50:13 providesgood lubrication without flooding and consequent churning and aerationof the oil. The unnumbered diametrically opposed A hole balances thegear.

Thus the oil is not required to fill the enclosure in order to lubricatethe teeth; the oil level in the sump need only be such that tube 78 isbelow its surface at all times, it being understood that the oil withinthe cup of gear 68 is not level but has the surface of a paraboloid ofrevolution which feeds oil to the gear tooth faces.

The last feature of major interest is the combined dipstick and ventwhich comprises a hollow copper tube 78 soldered into a brass pipe plug80 which is drilled with a through hole to accept the tube. The tube iscrimped together at the top to prevent entry of water; two diametricallyopposed 1 diameter holes, 82, through the tube wall allow adequateventing with good free board in case of ch PPY water.- TQ check oillevel the plug is un- 4 screwed and inverted so that vent tube 82reaches into the enclosure and becomes a dipstick registering the levelof oil in the sump.

The remainder of the structure is straight forward. Oil is drained fromthe sump by removing plug 84 from tapped hole 86 and tilting theassembly on its side. Stepped lands 88 and 90 in sleeve 36 accommodate aradial and an axial seal 92, 94 respectively, the latter bearing on theend of the hub 96 of impeller 12.

The function of the pump also needs little descriptionit will be notedthat during operation the space between the sump 34, 36 and the uppersurface of the impeller 12 fills with water to a greater or lesserextent. For this reason the upper and middle casing members have beenenlarged over the prior art to provide greater floatation and toaccommodate a greater proportion of the volute chamber.

It will be understood that although the construction has been explainedin some detail, it will be obvious to those skilled in the art thatvarious changes and modifications may be made therein without departingfrom the invention as defined by the appended claims.

I claim:

1. A buoyant centrifugal pump comprising:

a generally annular buoyancy member having a reentrancy on the lowersurface, the reentrancy being in the form of a portion of a centrifugalpump volute chamber and of a portion of the outlet therefrom, thebuoyancy member terminating inwardly at a diameter adjacent the voluteinner diameter,

a lightweight sheet material member fastened on the underside of thebuoyancy member and having such a shape as to form a pump inlet,

a lower impeller chamber wall, the remainder of the volute chamber andthe outlet therefrom,

a wall means detachably mounted on the upper side of the buoyancy memberand extending inwardly therefrom towards the impeller shaft so as toprovide an impeller chamber upper wall with a central hole therethrough,

an impeller having a maximum diameter smaller than the inner terminatingdiameter of the buoyancy member, the impeller being located between theimpeller chamber lower and upper walls,

an impeller shaft extending through the central hole of the impellerchamber upper wall, and

a power source above the impeller chamber upper wall suitably connectedto the impeller shaft.

2. A buoyant centrifugal pump as claimed in claim 1 wherein the impellerchamber upper wall means is downwardly dished and further comprises anintegral bearing sleeve and a seal for the impeller shaft, the downwarddishing of the impeller chamber upper wall me ns providing an oil sumpthereabove.

3. A buoyant centrifugal pump comprising:

a generally annular buoyancy member having a reentrancy on the lowersurface, the reentrancy being in the form of a portion of a centrifugalpump volute chamber and of a portion of the outlet therefrom, thebuoyancy member terminating inwardly at a diameter adjacent the voluteinner diameter,

a lightweight sheet material member fastened on the underside of thebuoyancy member and having such a shape as to form a pump inlet, a lowerimpeller chamber wall, the remainder of the volute chamber and theoutlet therefrom,

a wall means detachably mounted on the upper side of the buoyancymember, the wall means being dished inwardly and downwardly and havingan integral bearing sleeve and a seal so that the wall means providesboth an impeller chamber upper wall at the under surface and an oil sumpat the upper surface,

an impeller having a maximum diameter smaller than the inner terminatingdiameter of the buoyancy member, the impeller being located between theimpeller chamber lower and upper walls,

an impeller shaft extending through the bearing sleeve in the impellerchamber upper wall into the oil sump provided thereby,

an engine mounting plate cooperating with said Wall means so as to coverthe sump and thus provide an enclosure therewith,

a speed reduction device accommodated in said enclosure between saidwall means and said engine mounting plate, and

an internal combustion engine mounted upon said engine mounting plate,the drive shaft of the internal combustion engine being connected so asto drive the speed reduction device, and the speed reduction devicebeing connected to drive the impeller shaft.

4. A buoyant centrifugal pump as claimed in claim 3 wherein the driveshaft from the internal combustion engine extends through the enginemounting plate and said speed reduction device comprises a gear mountedon such drive shaft extension and a gear on the impeller shaft in directengagement with the engine drive shaft gear.

5. A buoyant centrifugal pump comprising:

a generally annular buoyancy member having a reentrancy on the lowersurface, the reentrancy being in the form of a portion of a centrifugalpump volute chamber and of a portion of the outlet therefrom, thebuoyancy member terminating inwardly at a diameter adjacent the voluteinner diameter,

a lightweight sheet material member fastened on the underside of thebuoyancy member and having such a shape as to form a pump inlet, a lowerimpeller chamber wall, the remainder of the volute chamber and theoutlet therefrom,

a wall means detachably mounted on the upper side of the buoyancymember, the wall means being dished inwardly and downwardly and havingan integral bearing sleeve and a seal so that the wall means providesboth an impeller chamber upper wall at the under surface and an oil sumpat the upper surface,

an impeller having a maximum diameter smaller than the inner terminatingdiameter of the buoyancy member, the impeller being located between theimpeller chamber lower and upper walls,

an impeller shaft extending through the bearing sleeve in the impellerchamber upper wall into the oil sump provided thereby,

an engine mounting plate cooperating with said wall means so as to coverthe sump and thus provide an enclosure therewith,

an internal combustion engine mounted upon said engine mounting plate,the drive shaft of the internal mounting plate, and

a speed reduction device accommodated in said enclosure comprising ahigh speed pinion gear on the engine drive shaft and an internal annulargear mounted on the impeller shaft and in driven relationship with thehigh speed pinion gear.

6. A buoyant centrifugal pump as claimed in claim 5 in which theinternal annular gear has a web connecting the hub to the teeth, andfurther comprises an oil scoop means adapted, upon rotation of theinternal annular gear, to gather oil from the sump and to deliver oil tothe internal teeth.

7. A buoyant centrifugal pump as claimed in claim 6 in which the scoopmeans is an inclined tube.

8. A buoyant centrifugal pump as claimed in claim 3 and furthercomprising a combined vent and oil dipstick which include:

a hollow plug releasably blocking a through hole in the engine mountingplate, and

a hollow tube integral with said plug and closed at the upper end, saidhollow tube having a substantial length relative to the dimension of theengine mounting plate hole and having at least one hole through the tubewall at the end distal from the plug, the tube Wall hole being of such adiameter as to inhibit the admission of water.

References Cited UNITED STATES PATENTS 3,397,647 8/1968 Daniel 1032183,461,807 8/1969 Morrison 103103 ROBERT M. WALKER, Primary Examiner

